In 1979, a crucified Eric Idle advised movie-goers to always look on the bright side of life. It seems that he needn’t have bothered. Psychological experiments have consistently shown that as a species, our minds are awash with a pervasive optimism.

We expect our future successes to overpower our past ones. Compared to an imaginary Joe Bloggs, we deem ourselves likely to live longer, more likely to have a successful career and less likely to suffer divorce or ill health. Even the most cynical of minds had a tendency for making similar, overconfident predictions.

Now, Tali Sharot and colleagues form New York University have pinpointed a neural circuit in the brain that generates this glass-half-full outlook.

Sharot asked 18 recruits to